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B-heptomino image
Pattern type Methuselah
Number of cells 7
Bounding box 4×3
Lifespan 148 generations
Final population 26
L/I 21.1
F/I 3.7
F/L 0.176
L/MCPS 21.1
Discovered by John Conway
Year of discovery 1970

The B-heptomino (or B-heptaplet, if the top-left cell is shifted one cell left) is a very common methuselah that evolves into three blocks, two gliders and a ship after 148 generations. Compare with Herschel, which appears at generation 20 of the B-heptomino's evolution. B-heptominoes acquired particular importance in 1996 due to David Buckingham's work on B tracks.

This pattern often arises with the cell at top left shifted one space to the left, producing a seven-bit polyplet that shares the same eight-bit descendant but is not technically a heptomino at all. This alternate form is shown as the input for elementary converter patterns such as BFx59H and BRx46B. This is standard practice for elementary conduits, since many of these conduits do in fact produce this alternate form as output.

The B-heptomino is considered a failed puffer or failed spaceship, since on its own it travels at c/2 for only a short time before being affected by its own trailing debris. However, it can be stabilized into a c/2 puffer or into a clean c/2 rake or spaceship. See, e.g., puffer 2, backrake 2, and ecologist.

In other rules

The B-heptomino is a stable puffer in many rules.

  • In B3/S23-e4e, it evolves into a (16,5)c/74 oblique spaceship.
  • In B3/S23-a, it is a glide-symmetric 10c/20 spaceship.
  • In B34ej5y6n/S23, it is an oblique quadratic replicator, one of only a few known.
  • In B36n/S2-i36c7c, it evolves into a glide-symmetric 9c/70 diagonal spaceship.

Image gallery

See also

External links